Interventions to reduce burnout among clinical nurses: systematic review and meta-analysis

Sporadic evidence exists for burnout interventions in terms of types, dosage, duration, and assessment of burnout among clinical nurses. This study aimed to evaluate burnout interventions for clinical nurses. Seven English databases and two Korean databases were searched to retrieve intervention studies on burnout and its dimensions between 2011 and 2020.check Thirty articles were included in the systematic review, 24 of them for meta-analysis. Face-to-face mindfulness group intervention was the most common intervention approach. When burnout was measured as a single concept, interventions were found to alleviate burnout when measured by the ProQoL (n = 8, standardized mean difference [SMD] = − 0.654, confidence interval [CI] =  − 1.584, 0.277, p < 0.01, I2 = 94.8%) and the MBI (n = 5, SMD = − 0.707, CI = − 1.829, 0.414, p < 0.01, I2 = 87.5%). The meta-analysis of 11 articles that viewed burnout as three dimensions revealed that interventions could reduce emotional exhaustion (SMD = − 0.752, CI = − 1.044, − 0.460, p < 0.01, I2 = 68.3%) and depersonalization (SMD = − 0.822, CI = − 1.088, − 0.557, p < 0.01, I2 = 60.0%) but could not improve low personal accomplishment. Clinical nurses' burnout can be alleviated through interventions. Evidence supported reducing emotional exhaustion and depersonalization but did not support low personal accomplishment.

www.nature.com/scientificreports/ Risk-of-bias assessment. To evaluate the risk of bias, we used the Cochrane's Risk of Bias 2.0 (RoB 2.0) for the randomized controlled trials and Risk of Bias in Non-randomized Studies of Interventions (RoBINS-I) for the quasi-experimental studies. Discrepancies were resolved through discussion. In addition, a funnel plot was utilized to evaluate the possibility of publication bias.

Data synthesis and meta-analysis.
For the systematic review, tables were used to classify article contents for descriptive analyses. For the meta-analysis, the R-4.1.1 program for Windows was used. In 16 articles, burnout was measured as a single concept using various instruments, while in 11 articles, burnout was measured as three dimensions: emotional exhaustion, depersonalization, and low personal accomplishment. Meta-analysis was conducted with the fixed effect model and the random effect model with 95% confidence interval, pooled mean differences, and weight of each article for each meta-analysis. The heterogeneity of the articles was calculated using the I 2 index. This research was exempted after review by the institutional review board at the institution of the principal investigator.

Results
Study selection. We retrieved 5271 articles from the initial search. After reviewing the title and abstract, 5188 were excluded (duplicates, no intervention study, no comparison group, not target population). During the full-text review, 59 articles were excluded (no full-text, duplicates, no intervention study, no comparison group, not target population). Through reference check, six articles were included. Finally, 30 articles were included in our final analysis (Fig. 1).

Risk-of-bias.
Risk-of-bias is described in Table 2. In general, the level of risk of bias for 12 randomized controlled trials was "some concern. " The level of risk of bias for the 18 quasi-experimental studies was "low risk of  www.nature.com/scientificreports/ bias" for 15 studies, "moderate risk of bias" for two studies, and non-assessable due to limited information for one study. The risk of publication bias was evaluated using a funnel plot (Fig. 2). The plot is symmetrical when publication bias is at minimum 58 . Studies with a small sample size were on the lower side, while those with a large sample size were on the opposite side. The small number of articles used in our study was a risk factor because it could affect the precision of the results. Among 30 articles, three articles 37,38,44 that did not conduct a post-test were excluded for meta-analysis. Sixteen articles measured burnout as a single concept [26][27][28]31,34,35,40,[45][46][47][49][50][51][52]54,56 and 11 measured burnout as three dimensions: emotional exhaustion, depersonalization, and low personal accomplishment 30,33,36,39,[41][42][43]48,53,55,57 . There was one outlier among articles that measured burnout as a single concept.

Discussion
In this systematic review and meta-analysis, we analyzed 30 and 24 articles, respectively. Among 30 articles, more than half (n = 19) were published in Asia. Although nurse burnout is a global phenomenon, the prevalence of nurse burnout studies conducted in Asia might indicate the significance of the issue of nurse burnout in Asian countries. This notion is supported by a recent meta-analysis study on the global prevalence of nurse burnout, which reported that Southeast Asia and the Pacific region had a significantly higher prevalence of nurse burnout among si× global regions 6 . In Asia, nurses encounter poor working conditions such as low nurse patient ratios 59 and a rapidly aging population. High prevalence of nurse burnout in Asian countries might have drawn the nurse administrators and nursing scholars to research on nurse burnout interventions.
Our systematic review revealed that a mindfulness-based program was the most frequently used intervention for nurse burnout. Meta-analysis studies 19 have shown that mindfulness-based programs are effective in reducing nurse burnout. However, burnout refers to a state of physical, mental, and social exhaustion that may require various interventions. A systematic review of health professional burnout programs revealed that a vast array of interventions have been adopted alone or in combination 24 . Although mindfulness-based programs are helpful in lowering burnout level, their role might be limited to managing burnout rather than preventing or managing situations for burnout 60 . In many cases, the causes of burnout are multifaceted, which include but are not limited to issues with limited manpower, working longer shifts, not having schedule flexibility, and responding to high www.nature.com/scientificreports/ work and psychological demands 11 . Systematic support to improve work environments and tailored programs to train nurses to prevent repeated situations are needed. All articles were appraised for risk of bias. The most concerning realm for risk of bias in both the randomized controlled trials and quasi-experimental studies was bias in the measurement of outcomes that were appraised as "some concern" or "moderate risk of bias. " As burnout is a subjective concept, all the interventions used a self-reported survey to measure the outcome, leading to a moderate risk of bias. To overcome this, biological indicators for burnout could be utilized. However, we would like to note that people are experts in their own feelings and psychological health. In measuring psychological concepts such as burnout, the concept of risk of bias should be re-assessed.
In our meta-analysis of articles that measured burnout as a single concept with ProQoL and MBI, the results favored intervention. Similarly, results of previous meta-analyses of various burnout interventions provided to health professionals reported that burnout could be reduced 23 . In this study, the authors argued that various factors, such as coping strategies, emotional regulation skills, and resilience, were enhanced through diverse burnout interventions and bridged health professionals' burnout to wellness. Likewise, various programs could be utilized solitarily or in combination to reduce nurse burnout.
When burnout was measured as three dimensions, emotional exhaustion and depersonalization were lowered, leaving no evidence for increasing low personal accomplishment. In contrast, a recent meta-analysis study on burnout intervention for primary healthcare professionals reported that interventions had beneficial effects on all three dimensions of burnout, including low personal accomplishment 61 . In the previous meta-analysis study, 78.5% of the participants were physicians, while only 20.1% were nurses. This was one of the most significant differences between the studies. The nature of the profession in achieving personal accomplishment may explain the differences in intervention effect on low personal accomplishment. Personal accomplishment for nurses may be more closely tied to a workplace system. For instance, a study that measured personal accomplishment found that it was positively correlated with aspects of the workplace such as control, community, fairness, and values 62 . In accordance with this argument, a meta-analysis that examined the long-term effect of burnout intervention on nurses found that improvement in low personal accomplishment lasted only six months, whereas improvement in emotional exhaustion and depersonalization lasted a year 20 . The authors of this study also explained that low personal accomplishment is difficult to change in the long term because it is reliant on the work environment. Another possible reason for the burnout intervention not favoring low personal accomplishment might be owing to the contents of the intervention focusing on problem-solving skills, such as stress reduction, coping with the problem, and empowering the participants, which are helpful for emotional exhaustion and depersonalization.
Implications for future research are suggested as follows. This study revealed that the majority of burnout interventions for clinical nurses were delivered as face-to-face group programs, which could be challenging to implement during a pandemic such as COVID-19. Combining online and offline burnout programs may be an option for reducing the risk of infection. Despite the fact that clinical nurses benefit from burnout programs, they may require consistent support and feedback to continue the program 63 . Continual active feedback may be necessary for the implementation and maintenance of the burnout program for clinical nurses. A number of scholars view burnout as three dimensions in line with the ICD-11 definition of burnout and meta-analysis studies on the prevalence and risk factors for burnout explained burnout as three dimensions 6,64 , meaning there is ample evidence on the dimensions of burnout. However, when examining the effect of burnout interventions, burnout is often measured as a single concept. Burnout interventions should be designed to target all three areas. Additionally, more time and effort might be needed to promote personal accomplishment.

Limitations
In this study, we focused on nurses providing direct care in hospitals, excluding those who worked in outpatient clinics. Thus, our findings are limited to clinical nurses. The articles' language was limited to English and Korean, half of which were in Korean. In addition, we limited our search to the past 10 years to reflect the reality of the burnout intervention effect, which may have caused selection bias. When the risk of bias was appraised, we identified some concerns, including moderate concerns. In addition, articles analyzed in this study used different instruments to measure burnout. We acknowledge the heterogeneity of the data, which is assumed by meta-analysis study. Thus, readers of this article should be aware of the risk of bias in the results and heterogeneity of the articles in instruments. The protocol of this systematic review and meta-analysis was not registered.

Conclusions
Thirty articles were included in the systematic review and 24 in the meta-analysis. Most of the evidence for nurse burnout was based on face-to-face group programs, which could be transformed into a virtual space in the post-COVID-19 era. Pooled analysis suggested that interventions could reduce burnout when measured as a single concept and reduce the emotional exhaustion and depersonalization dimensions of burnout. However, we could not find evidence for burnout interventions effectively promoting personal accomplishment.

Data availability
The datasets generated and/or analyzed during the current study are not publicly available due to the IRB restriction but are available from the corresponding author on reasonable request.